Coagulation performance evaluation of alginate as a natural coagulant for the treatment of turbid water

Alginates are quite abundant in nature as they occur both as a structural component in marine brown algae (Phaeophyceae) comprising up to 40% of dry matter and as capsular polysaccharides in soil bacteria. Alginic acid is the only polysaccharide, which naturally contains carboxyl groups in each constituent residue, and possesses various abilities for functional materials. Experiments were carried out for the water of turbidity 300 NTU. Alginate as such doesn't act as a coagulant instead it should be converted to calcium alginate by adding calcium ions. Calcium chloride was used for imparting calcium ions necessary for the reaction. The dosage of calcium was fixed as 50 mg/L, 75 mg/L, 100 mg/L, 150 mg/L, 200 mg/L, and alginate doses between 2 to 10 mg/L. Calcium dosage below 50 mg/L was not sufficient enough for the formation of egg-box structure which is responsible for the coagulation and flocculation process. For the mechanism of charge neutralization to take place effectively, calcium should be added first followed by alginate. pH and conductivity of the sample remain constant before and after the treatment. The dosage of alginate required for the treatment is less so the cost of treatment also will be very less, thus alginate can replace the usage of chemical coagulants like alum.

Melt electro-written scaffolds with box-architecture support orthogonally-oriented collagen

Melt Electro-Writing (MEW) is a state-of-the-art technique that supports fabrication of 3D, precisely controlled and reproducible fiber structures. A standard MEW scaffold design is a box-structure, where a repeat layer of 90° boxes is produced from a single fiber. In 3D form (i.e., multiple layers), this structure has the potential to mimic orthogonal arrangements of collagen, as observed in the corneal stroma. In this study, we determined the response of human primary corneal stromal cells and their deposited fibrillar collagen (detected using a CNA35 probe) following 6-weeks in vitro culture on these box-structures made from poly(ε-caprolactone). Comparison was also made to glass substrates (topography-free) and electrospun poly(ε-caprolactone) fibers (aligned topography). Cell orientation and collagen deposition were non-uniform on glass substrates. Electrospun scaffolds supported an excellent parallel arrangement of cells and deposited collagen to the underlying architecture of aligned fibers, but there was no evidence of bidirectional collagen. In contrast, MEW scaffolds encouraged the formation of a dense, interconnected cellular network and deposited fibrillar collagen layers with a distinct orthogonal-arrangement. Collagen fibrils were particularly dominant through the middle layers of the MEW scaffolds’ total thickness and closer examination revealed these fibrils to be concentrated within the pores’ central regions. With the demand for donor corneas far exceeding the supply - leaving many with visual impairment - the application of MEW as a potential technique to recreate the corneal stroma with spontaneous, bidirectional collagen organization warrants further study.

Experimental Study on Mechanical Properties of a Medium Size Box-Type Corrugated Steel Bridge

Different from an arch bridge, the load-carrying capacity of a box structure mainly depends on the bending capacity of corrugated steel. This paper explores the mechanical properties of a corrugated steel box bridge. The mechanical properties of a 13 m span corrugated steel box bridge under static and dynamic loads were tested. Three static load conditions were tested, and four dynamic load conditions were tested, including 20 km/h, 40 km/h, 60 km/h, and 80 km/h. Through the analysis of section strain, vault displacement, dynamic strain, and internal force, the following conclusions can be drawn: (1) when the static load changes from the right arch foot and vault to the left arch foot, the strain value of each measuring point continues to increase, which may be caused by the accumulation of deformation due to the adjustment of the stress state of the soil and corrugated steel caused by loading; (2) the displacement change in the test is more sensitive than the strain change; (3) the vault strain reaches the maximum value at a specific speed of 60 km/h. This is related to the structural resonance caused by vehicle operation, and the natural frequency of the corrugated steel box bridge can be determined by a field vehicle dynamic load test; (4) the damping value of an embedded corrugated steel bridge is large, and the energy dissipation capacity is strong, which is very beneficial to structural earthquake resistance and to reducing the structural resonance under traffic load; (5) the dynamic increasing strain coefficient is less than 1, which means that the strain caused by a dynamic load is far less than that caused by a static load, and it reaches the maximum value at a certain speed (60km/h); (6) the maximum bending stress and maximum axial stress of the corrugated steel box bridge tested in this paper are basically the same, which indicates that the axial stress of the box structure cannot be ignored. However, the box structure design method proposed in the CHBDC code does not consider the axial stress, so it is necessary to further improve the box structure design method; (7) most of the axial force of a box corrugated steel bridge is tensile force. The pavement structure layer has an effect on the overall performance of the corrugated steel box bridge, which is similar to the decompression plate: it makes the overall stress (I ∼ V section) more uniform and the bending moment smaller.

Selective interference: Emergent complexity informed by programmatic, social and performative criteria

<p>Parametric design tools and visual programming languages are fast becoming an important part of the architects design process. A review of current literature notes that the barrier to entry into the medium is lowering while the power of the tools available is increasing. The purpose of this research is to use these emerging tools to explore complex architectural issues related to space planning and massing. This research aims to bring these aspects of the design process together to generate an architecture where programme and aesthetic are derived in equal measure by the architect and the computer. The project began with a series of technical studies focusing primarily on space planning, massing, site analysis and circulation with the purpose of using an amalgamation of these techniques to develop into a final generative algorithm. These ideas are explored through an open ended design process of iterative research and testing, self and peer review, development and critical reflection. The viability of the algorithm is then tested through the generation a number of test buildings, across variety of sites. In order to provide a direction and author a degree of creative friction within the research process, the projects are framed around the development of a mid-size, urban sited secondary school. The final algorithm provides constraints in such a way that the architecture evolves in a natural, predictable way that can still surprise and inform, as well as consistently producing viable, interesting iterations of buildings. This process, described as an “open box” structure, produced a wide variety of working concepts and provided a high level of control as a designer.</p>

Selective interference: Emergent complexity informed by programmatic, social and performative criteria

<p>Parametric design tools and visual programming languages are fast becoming an important part of the architects design process. A review of current literature notes that the barrier to entry into the medium is lowering while the power of the tools available is increasing. The purpose of this research is to use these emerging tools to explore complex architectural issues related to space planning and massing. This research aims to bring these aspects of the design process together to generate an architecture where programme and aesthetic are derived in equal measure by the architect and the computer. The project began with a series of technical studies focusing primarily on space planning, massing, site analysis and circulation with the purpose of using an amalgamation of these techniques to develop into a final generative algorithm. These ideas are explored through an open ended design process of iterative research and testing, self and peer review, development and critical reflection. The viability of the algorithm is then tested through the generation a number of test buildings, across variety of sites. In order to provide a direction and author a degree of creative friction within the research process, the projects are framed around the development of a mid-size, urban sited secondary school. The final algorithm provides constraints in such a way that the architecture evolves in a natural, predictable way that can still surprise and inform, as well as consistently producing viable, interesting iterations of buildings. This process, described as an “open box” structure, produced a wide variety of working concepts and provided a high level of control as a designer.</p>

The effect of modal properties of crash box structures with trigger mechanisms towards the crashworthiness by using finite element analysis

In the automotive structure, there are different components that utilise aluminium alloy (AA) sheets and it is used widely in the car body-in-white which comprise bumpers and the crash box structure at the front end of the car which specifically designed to withstand the event of collision. As the structures are also experiencing dynamic loading, it were also a concern for the structures to show satisfied modal properties. In this study, the modal properties of the crash box structures are investigated along with the effect of the modal properties towards the crashworthiness behaviour of the structure itself with the approach of finite element analysis. Experimental modal analysis was also done to further validating the finite element analysis of the modal properties. Three different designs of trigger mechanisms are applied towards the crash box structure to observe on both findings. For the connector element, equivalent nodes of both parts of the crash box structures are used. For the results, the correlation from both findings did show that the presence of trigger mechanism did decreased the magnitude of natural frequencies as well as the mode shape as shown by crash box type 3 by 9.50% and for the crashworthiness output, the crashworthiness behaviour of the crash box with trigger mechanisms were better in term of the collisions phases indicated by the primary peak force and the secondary peak force from the force-displacement curve as also shown by crash box structure type 3 with the percentage of 22.59%. The study does shows that the stiffness and mass distribution due to the presence of trigger mechanism do affect the modal properties of a structure as well as its crashworthiness output.